The apparatus of the present invention is intended primarily for use in carrying out a method of growing perennials invented by the present applicant. This method is the subject of U.S. Pat. No. 5,331,908, issued Jul. 26, 1994. The method involves starting a plant in a container and then placing the plant still in the container in a field for further growth. During the ensuing dormant season, the plant is harvested by undercutting feeder roots extending downwardly out of the container and removing the plant and container from the field. After harvesting, the plant foliage is preferably trimmed for transportation or storage. The apparatus of the present invention has been developed by the applicant to automate the trimming procedure.